Real-time data analysis at the LHC: present and future

The Large Hadron Collider (LHC), which collides protons at an energy of 14 TeV, produces hundreds of exabytes of data per year, making it one of the largest sources of data in the world today. At present it is not possible to even transfer most of this data from the four main particle detectors at the LHC to "offline" data facilities, much less to permanently store it for future processing. For this reason the LHC detectors are equipped with real-time analysis systems, called triggers, which process this volume of data and select the most interesting proton-proton collisions. The LHC experiment triggers reduce the data produced by the LHC by between 1/1000 and 1/100000, to tens of petabytes per year, allowing its economical storage and further analysis. The bulk of the data-reduction is performed by custom electronics which ignores most of the data in its decision making, and is therefore unable to exploit the most powerful known data analysis strategies. I cover the present status of real-time data analysis at the LHC, before explaining why the future upgrades of the LHC experiments will increase the volume of data which can be sent off the detector and into off-the-shelf data processing facilities (such as CPU or GPU farms) to tens of exabytes per year. This development will simultaneously enable a vast expansion of the physics programme of the LHC's detectors, and make it mandatory to develop and implement a new generation of real-time multivariate analysis tools in order to fully exploit this new potential of the LHC. I explain what work is ongoing in this direction and motivate why more effort is needed in the coming years.Comment: Contribution to the proceedings of the HEPML workshop NIPS 2014. 20 pages, 5 figure

Measuring direct CP violation in four body baryonic B decay modes at LHCb

Baryonic B decays may allow direct measurements of CP violation at LHCb. Direct CP violation in the decay mode B+ -> ppK*+ has been predicted to be 22% in the Standard Model, while it is predicted to be only 1% in B0 -> ppK*0. Both modes are believed to proceed through penguin diagrams, making them sensitive to new physics effects which could significantly alter the observed level of CP violation. LHCb's potential to observe CP violation in these decay modes is discussed. The decay mode B+ -> ppK*+ is expected to yield approx. 400 and B0 -> ppK*0 approx. 1600 signal events with 2fb^-1 of data taking. LHCb can expect to measure CP violating asymmetries with a precision of approx. 7% in B+ -> ppK*+ and approx. 3.5% in B0 -> ppK*0 with 2fb^-1 of data taking, and these measurements are not expected to be systematics limited

Quark flavour physics: status and future prospects

Quark flavour physics is the study of hadrons, their properties, and their decays into other particles. As a discipline it simultaneously catalogues the nature of physical states within the Standard Model of particle physics, and in doing so tests the consistency and completeness of the Standard Model's description of reality. Following the discovery of the Higgs field, it is more essential than ever to critically examine the Standard Model's own coherence. Precision studies of quark flavour are one of the most sensitive experimental instruments for this task. I give a brief and necessarily selective overview of recent developments in quark flavour physics and discuss prospects for the next generation of experiments and facilities, with an emphasis on the energy scales of beyond Standard Model physics probed by these types of measurements.Comment: Invited review for IJMP

Monte Carlo Independent Lifetime Fitting at LHCb in Lifetime Biased Channels

Lifetime measurements at LHCb will help in detector calibration as well as providing constraints on lifetime differences in the $B_s$ system and other theoretical models. In order to exploit the full range of decays available in LHCb, it is important to have a method for fitting lifetimes in hadronic channels, which are biased by the impact parameter cuts in the trigger. We have investigated a Monte Carlo simulation independent method to take into account the trigger effects. The method is based on calculating event by event acceptance functions from the decay geometry and does not require any external input. This note presents current results with this method for both the full LHCb Monte Carlo for the channel $B^{0}_{d} \rightarrow D^{-} \pi^{+}$ and a toy Monte Carlo for the same channel, including a discussion of the expected statistical precision on lifetime measurements using this method once LHCb is operational

A Monte Carlo simulation free method of measuring lifetimes using event-by-event acceptance functions at LHCb

A set of innovative methods and tools for precision lifetime and lifetime-difference measurements in hadronic B decays at LHCb is presented. All methods are purely data-driven and Monte Carlo simulation independent, a particularly important feature if lifetime measurements are to be made in the early period of LHCb's data taking. The methods and tools are shown to work in detailed simulation studies, including both Toy and Full Monte Carlo simulation studies of possible systematic biases in the measurements

Patients' preferences for subcutaneous trastuzumab versus conventional intravenous infusion for the adjuvant treatment of HER2-positive early breast cancer: final analysis of 488 patients in the international, randomized, two-cohort PrefHer study

PrefHer revealed compelling and consistent patient preference for subcutaneous (s.c.) trastuzumab, regardless of delivery by single-use injection device or hand-held syringe. s.c. trastuzumab was well-tolerated and safety data, including immunogenicity, were consistent with previous reports. No new safety signals were identified compared with the known intravenous trastuzumab profile in early breast cance

A Roadmap for HEP Software and Computing R&D for the 2020s

Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.Peer reviewe

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions